Spatiotemporal Evolution and Emergence of Frontier Malaria Mosaics in the Brazilian Amazon

Malaria is a major global health problem, including the Brazilian Amazon region. The theory of frontier malaria—linking agricultural expansion, migration, and road networks to altered land cover and disease transmission—is increasingly inadequate for contemporary Amazonian frontiers. Instead, we propose the concept of frontier malaria mosaics, reflecting diverse occupational profiles, mobility patterns, rural-urban connectivity, and land uses. As malaria declines in the Amazon, transmission becomes highly focal, clustering in localized areas with distinct characteristics. Using locality-level data from Brazil’s Malaria Surveillance System and a novel method to identify nearly all case locations, we analyze spatiotemporal evolution via parasite species, infection origin, land use, settlement patterns, and sociodemographics. Annualized indicators enable cross-period comparisons. Through cluster regionalization, we reveal distinct low- and high-transmission mosaics, each shaped by successive government policies. This approach overcomes key data limitations and demonstrates how local spatial configurations scale into regional patterns over time.